I inherited some burton mittens from my brother in law who has given up shredding.
Anyway the removable inner part was thin and crappy so I use fingered thicker inner gloves from my Mizuno gortex gloves.
Works out great waterproofing is solid and super warm. They are nice and long perfect in deep pow which is abundant where I ride (Japan).
Seems others also found what they want with this type of combo.
Only down side is no goggle wiper.

got some nice dakine mitts, dont know the exact type. they've been bulletproof. also had a pair of swany gloves that would keep my dry for a long time. Swany's were probably my favorite but i cant find em anywhere

im a huge fan of mittens when it comes to keeping my hands warm, so far the best ive found is candy grind handbag mitts.they lasted me about 4-6 month of riding with not many days off snow while most gloves ive had were torn to shreds within a month maybe 2 or 3 if i was lucky.

Trying to find good gloves is like searching for a needle in a haystack. 99% are crap and it's near impossible to tell if a pair is good until you use them a bunch.
That being said, I find the ski companies who have been around longer make better products.
Hestra, Dakine, and North Face are a few of the better ones. Burton are usually good.
Keep in mind that each company makes a variety of models... the full spectrum from shitty to excellent.

I bought a pair of pow tantos for this season. They fell like an awesome glove, they are super comfy and the wrist strap is tight so no snow gets in but doesn't cut off circulation. They are sized small, so buy a size up. I'd almost recommend 2 sizes up as for me I bought 1 size up and the length was perfect however the glove was tight. I didn't have a ton of dexterity but they need to be worked in. The water proofing us a cheaper material than gortex but functions the same way, since I haven't used them this year I cannot say how it performs. All in all it's a comfy well built glove and if they prove durable, which I read they are I can see myself defiantly buying another pair